Disallow changes to previously successfully applied scripts

README.md

@@ -192,6 +192,7 @@ Elasticsearch-Evolution can be configured to your needs:
 -   **placeholderSuffix** (default=}): Suffix of placeholders in migration scripts.
 -   **historyIndex** (default=es_evolution): Name of the history index that will be used by Elasticsearch-Evolution. In this index Elasticsearch-Evolution will persist his internal state and tracks which migration script has already been executed.
 -   **historyMaxQuerySize** (default=1000): The maximum query size while validating already executed scripts. This query size have to be higher than the total count of your migration scripts.
+-   **validateOnMigrate** (default=true): Whether to fail when a previously applied migration script has been modified after it was applied.
 
 ### 5.1 Spring Boot
 
@@ -288,7 +289,7 @@ ElasticsearchEvolution.configure()
 
 ### v0.4.1-SNAPSHOT
 
-- ...
+- Previously applied migration scripts are now checked for modifications and rejected if they've been modified after they were applied. The old behaviour can be restored by setting the new configuration parameter `validateOnMigrate` to false (default true).
 
 ### v0.4.0
 

elasticsearch-evolution-core/src/main/java/com/senacor/elasticsearch/evolution/core/ElasticsearchEvolution.java

@@ -168,6 +168,7 @@ protected MigrationService createMigrationService() {
                 10_000,
                 getRestClient(),
                 ContentType.parse(getConfig().getDefaultContentType()),
-                getConfig().getEncoding());
+                getConfig().getEncoding(),
+                getConfig().getValidateOnMigrate());
     }
 }

elasticsearch-evolution-core/src/main/java/com/senacor/elasticsearch/evolution/core/api/config/ElasticsearchEvolutionConfig.java

@@ -83,6 +83,11 @@ public class ElasticsearchEvolutionConfig {
      */
     private int historyMaxQuerySize = 1_000;
 
+    /**
+     * Whether to fail when a previously applied migration script has been modified after it was applied.
+     */
+    private boolean validateOnMigrate = true;
+
     /**
      * Loads this configuration into a new ElasticsearchEvolution instance.
      *
@@ -236,6 +241,15 @@ public ElasticsearchEvolutionConfig setHistoryMaxQuerySize(int historyMaxQuerySi
         return this;
     }
 
+    public boolean getValidateOnMigrate() {
+        return validateOnMigrate;
+    }
+
+    public ElasticsearchEvolutionConfig setValidateOnMigrate(boolean validateOnMigrate) {
+        this.validateOnMigrate = validateOnMigrate;
+        return this;
+    }
+
     @Override
     public String toString() {
         return "ElasticsearchEvolutionConfig{" +
@@ -251,6 +265,7 @@ public String toString() {
                 ", placeholderReplacement=" + placeholderReplacement +
                 ", historyIndex='" + historyIndex + '\'' +
                 ", historyMaxQuerySize=" + historyMaxQuerySize +
+                ", validateOnMigrate=" + validateOnMigrate +
                 '}';
     }
 }

elasticsearch-evolution-core/src/main/java/com/senacor/elasticsearch/evolution/core/internal/migration/execution/MigrationServiceImpl.java

@@ -37,17 +37,20 @@ public class MigrationServiceImpl implements MigrationService {
     private final RestClient restClient;
     private final ContentType defaultContentType;
     private final Charset encoding;
+    private final boolean validateOnMigrate;
 
     public MigrationServiceImpl(HistoryRepository historyRepository,
                                 int waitUntilUnlockedMinTimeInMillis,
                                 int waitUntilUnlockedMaxTimeInMillis,
                                 RestClient restClient,
                                 ContentType defaultContentType,
-                                Charset encoding) {
+                                Charset encoding,
+                                boolean validateOnMigrate) {
         this.historyRepository = requireNonNull(historyRepository, "historyRepository must not be null");
         this.restClient = requireNonNull(restClient, "restClient must not be null");
         this.defaultContentType = requireNonNull(defaultContentType);
         this.encoding = requireNonNull(encoding);
+        this.validateOnMigrate = validateOnMigrate;
         this.waitUntilUnlockedMinTimeInMillis = requireCondition(waitUntilUnlockedMinTimeInMillis,
                 min -> min >= 0 && min <= waitUntilUnlockedMaxTimeInMillis,
                 "waitUntilUnlockedMinTimeInMillis (%s) must not be negative and must not be greater than waitUntilUnlockedMaxTimeInMillis (%s)",
@@ -185,9 +188,20 @@ List<ParsedMigrationScript> getPendingScriptsToBeExecuted(Collection<ParsedMigra
             ParsedMigrationScript parsedMigrationScript = orderedScripts.get(i);
             if (!protocol.getVersion().equals(parsedMigrationScript.getFileNameInfo().getVersion())) {
                 throw new MigrationException(String.format(
-                        "The logged execution in the Elasticsearch-Evolution history index at position %s is version %s and in the same position in the given migration scripts is version %s! Out of order execution is not supported. Or maybe you have added new migration scripts in between or have to cleanup the Elasticsearch-Evolution history index manually",
+                        "The logged execution in the Elasticsearch-Evolution history index at position %s " +
+                                "is version %s and in the same position in the given migration scripts is version %s! " +
+                                "Out of order execution is not supported. Or maybe you have added new migration scripts " +
+                                "in between or have to cleanup the Elasticsearch-Evolution history index manually",
                         i, protocol.getVersion(), parsedMigrationScript.getFileNameInfo().getVersion()));
             }
+            // failed scripts can be edited and retried, but successfully executed scripts may not be modified afterwards
+            if (validateOnMigrate && protocol.isSuccess() && protocol.getChecksum() != parsedMigrationScript.getChecksum()) {
+                throw new MigrationException(String.format(
+                        "The logged execution for the migration script at position %s (%s) " +
+                                "has a different checksum from the given migration script! " +
+                                "Modifying already-executed scripts is not supported.",
+                        i, protocol.getScriptName()));
+            }
 
             if (protocol.isSuccess()) {
                 res.remove(parsedMigrationScript);

elasticsearch-evolution-core/src/test/java/com/senacor/elasticsearch/evolution/core/internal/migration/execution/MigrationServiceImplIT.java

@@ -57,7 +57,7 @@ void OK_indexDocumentIsWrittenToElasticsearch(String versionInfo, EsUtils esUtil
 
             MigrationServiceImpl underTest = new MigrationServiceImpl(historyRepositoryMock,
                     0, 0, restHighLevelClient.getLowLevelClient(),
-                    defaultContentType, encoding);
+                    defaultContentType, encoding, true);
 
             MigrationScriptProtocol res = underTest.executeScript(script).getProtocol();